C++改变图像颜色

#include<opencv2/opencv.hpp>
#include<opencv2/imgproc.hpp>

using namespace std;
using namespace cv;

int main()
{
	Mat img,img2;
	img = imread("E:/test.jpg");
	imshow("BGR", img);
	int i = 0; 
	int j = 0;
	int cPointB, cPointG, cPointR;
	for (i = 1; i < img.rows; i++)
		for (j = 1; j < img.cols; j++)
		{
			cPointB = img.at<Vec3b>(i, j)[0];
			cPointG = img.at<Vec3b>(i, j)[1];
			cPointR = img.at<Vec3b>(i, j)[2];
			if (cPointB > 100 & cPointR < 100 & cPointG < 100)
			{
				img.at<Vec3b>(i, j)[0] = 0;
				img.at<Vec3b>(i, j)[1] = 0;
				img.at<Vec3b>(i, j)[2] = 0;
			}

		}
	imshow("da", img);

	waitKey(0);
	system("pause");
	return 0;
}